Revised floodplain maps soak De Meadows

Letters were sent Thursday to 40 De Soto homeowners, four businesses and one industrial plant informing them that revised maps would place their homes or businesses within Kill Creek's 100-year floodplain.

Chet Belcher, storm water engineer for the Johnson County Storm Water Management Program, said a two-year study determined the lower Kill Creek watershed's 100-year floodplain was four feet higher than shown on current Federal Emergency Management Agency maps. A 100-year flood means a flood of such severity has a 1-percent chance of happening in a calendar year.

The county undertook an update of all its seven major watersheds after heavy flooding in October 1998 in the eastern part of the county, Belcher said. Although the Kill Creek work was nearly done, the report won't be submitted to FEMA until studies on watersheds with less development pressure in southwest Johnson County were completed. He anticipated the complete report would be forwarded to FEMA next fall.

It is expected FEMA would adopt the new maps in June 2007, Belcher said.

Once that was done, homeowners would have a new expense, said De Soto realtor Dan Gulley.

"Mortgage lenders and insurance companies use FEMA maps to determine who must purchase flood insurance," he said.

As for resale value, Gulley said the floodplain designation shouldn't hurt because of the relatively small cost of flood insurance. But he added, "It would definitely be a drawback."

The letter from City Engineer Mike Brungardt advises home and business owners to notify their mortgage companies of the coming change. It also invites them to an informational meeting at 7 p.m. Wednesday at De Soto City Hall, 32905 W. 84th St.

Thirty-nine of the 40 homes are in the eastern section of De Meadows. However, some homes in the area will not be affected by the change in maps.

The De Meadows homes are joined by one home in Oak Country, Huhtamaki and four businesses along Lexington Avenue east of the Community Center.

It is unusual for floodplain maps to change so drastically without major development upstream, Belcher said.

"It is because basically the difference found in the level of detail," he said. "The old FEMA floodplain maps were as good as the level of technology they had. We have much better topography and monitoring systems now that realistically reflect the flooding situation in the county."

In addition to the letters to those with homes found to be in the floodplain because of the study, letters would be sent to those with homes or businesses on Kill Creek tributaries in the new floodplain.

Although the study would place those sites at risk in a 100-year flood, FEMA does not normally include smaller tributaries on its official maps, the letter states. Letters will also be sent to those with property near the creek that will remain out of the new floodplain.

The Kill Creek study also includes what Belcher called "preliminary proposals" about how to lower the risks of flooding in De Soto. Suggestions include possible berms, but the best flood protection would be realized with the building of retention ponds upstream.

One proposal, which would remove all but five De Soto homes from the Kill Creek floodplain, would be to build a "retention pond" south of 95th Street. It might be a pond in the language of engineers, but the reservoir envisioned would be twice the size of Gardner Lake and would flood bottomland in Sunflower Quarry and the Sunflower Army Ammunition Plant, perhaps further complicating already thorny issues at those two sites.

The other proposed remedy would be to build two smaller lakes further upstream at about 135th Street. Again small is relative. Both lakes would be about the size of Gardner Lake.

Although the county took the lead on the watershed study with the city's cooperation, developing flood protection solutions would be the city's responsibility, Belcher said.

However, the county does have a 1/10-cent sales tax that helps pay for projects accepted by the Johnson County Storm Water Advisory Council, which had membership from every county city, he said.

At the conclusion of the county watershed study, the city could apply to the program to pay for its proposed flood control program, Belcher said. If approved, the county SMAC program would provide 75 percent of the money needed for the project, he said.